Surveillance cameras, and the sophisticated software packages that go with them, have become big business. Many small- and medium-sized cities across American are spending hundreds of thousands of dollars on cameras and software to watch their residents.

These systems use some of the same kinds of technology the New York Police Department has deployed in lower Manhattan to catch terrorists. But many cities are now using the technology for policing as mundane as preventing vandalism at parks.

A case in point: Elk Grove, Calif. Elk Grove is a sleepy suburb of Sacramento with a modest crime rate. It's bordered to the south and west by wide-open ranch land. Last week I found myself sitting on a swing in Miwok Park, watching toddlers, kids and dog walkers. It couldn't have been a sleepier scene.

Nonetheless, I was being watched. There was a camera right above my head.

"I didn't even know that one was there," said Chelsea Yokkum, who was playing with her son.

Nearby, a couple was lying on a picnic blanket, snuggling. When I walked up, interrupting, they packed up to go. They said they knew there was a camera above their head, but that they had no idea what happened to the video feed.

It turns out it's sent directly to the Elk Grove Police Department.

"That is kind of scary in a sense," said the man, who declined to give his name. "Knowing that people are watching, no matter what." He's not alone. Many folks in Elk Grove who told me they are apprehensive about these cameras didn't want to speak on the record and didn't want to be identified.

Laura Donohue, a Georgetown University law professor who studies surveillance technology, says that kind of reaction to surveillance is common. She says proponents of cameras often argue that people with nothing to hide have nothing to fear.

The mindset, she says, is, "If you are not willing to submit to this, you must somehow be doing something that is illegal."

She adds: "I think this is simply false."

Elk Grove has invested hundreds of thousands of dollars on surveillance, and it plans to spend more.

Lawrence Park playground burned to the ground in April, the result of a suspected arson. "I'd love to add a camera to this park if we can find the budget for it," says Bob Roessler, the administrator of the parks and recreation department.

Roessler says the department has already installed more than 30 cameras in parks across the city at a cost per camera of roughly $10,000. While the parks officials install, pay for and maintain these cameras, the video is shipped directly to the police department.

Across town, Chris Hill, IT manager for the Elk Grove Police Department, is the man in charge of building this network. When I visited, he showed me how video is accessible to dispatchers and showed off a rack of servers — all devoted to collecting more than 100 video feeds from all over the city.

Hill has built a system that's flexible and scalable. More than 100 feeds are viewable and searchable from his desk. "You can get camera feeds, you can make any screens you want, you can search any video," he says.

We lean over and watch men and women streaming in and out of a gym more than two miles away. "This was a known spot in the city of Elk Grove that had a high rate of car burglaries," Hill says.

We watch a woman open up her minivan door. Hill tracks her as she gets in and drives out of the lot. Then he zooms in to read her license plate.

It would take a single officer more than four days to watch all the video recorded by the Elk Grove police in an hour — but Hill would like to get even more.

"We actually have a pilot project coming up — hopefully shortly — with a local retailer that will be giving us access to their parking lot cameras," he says. Eventually he'd also like to work with local banks to get ATM camera feeds.

But Hill doesn't want Elk Grove's officers spending time watching parking lots and writing down plate numbers. Instead, there's software that can do that for them. To see how, I traveled to the offices of 3VR in San Francisco. The company makes the software that Elk Grove uses to sift through its recordings.

"Most people don't understand that putting more cameras [up] doesn't necessarily yield more information," says Al Shipp, 3VR's CEO. The company offers facial recognition, license plate readers and object-based searches. Elk Grove doesn't use all of these services yet, but it could add new ones at any time.

"Those are search arguments you can do with our technology and literally sort through weeks of video in a few seconds," he says.

Software like this can alert the police when someone enters a park after dark. Or it can search for a face.

Diego Simkin, a technician at 3VR, shows me a search for a suspect in a possible bank fraud. He clicks and, within seconds, there are pictures of the same man walking into multiple banks on different days up on the screen.

"I have the ability to ... search against multiple cameras on that system or multiple systems," Simkin says. 3VR's corporate clients are already using these kinds of searches.

These technologies are a major draw for police in Elk Grove and departments across the country. The video analytics industry is growing by 30 percent per year and the software alone is poised to become a billion-dollar business.

"The idea that all of this information will be fed into one place, I think is a game-changer in terms of how we look at our world," says Donohue. She says that while it's reasonable to expect someone will see you lying in a public park, "you do have a reasonable expectation that nobody is going to be following you around 24 hours a day, seven days a week, everywhere you go."

Donohue worries that that's where these systems seem to be headed.

Copyright 2018 NPR. To see more, visit http://www.npr.org/.

STEVE INSKEEP, HOST:

Let's hear another installment of the NPR Cities Project.

UNIDENTIFIED WOMAN: If other cities can do it, we can do it.

UNIDENTIFIED MAN #1: This whole building is based on technology.

UNIDENTIFIED MAN #2: This is an old city but we add on the latest technologies.

INSKEEP: OK. The NPR Cities Project is our exploration of urban innovation, using technology to become more efficient - or try to be safer. Today, we'll focus on surveillance cameras and sophisticated software that goes with them. They become big business, sold to cities of all sizes. NPR's Stephen Henn reports from a suburb of Sacramento, California called Elk Grove.

STEVE HENN, BYLINE: I'm sitting on a swing in Miwok Park in Elk Grove, California. The morning commute here is made up of toddlers, kids, dog walkers, some moms, but right now I'm being watched almost as carefully as I would be if I were on Wall Street. There's a camera right over my head.

CHELSEA YOKKUM: I didn't even know that one was there.

HENN: Chelsea Yokkum is playing with her son. Nearby a couple is lying on a picnic blanket kind of snuggling.

UNIDENTIFIED MAN #3: We were just kind of enjoying each others' company, I guess you could say.

HENN: They know there is a camera here but - do you know where that camera feed goes or what happens to it?

UNIDENTIFIED MAN #3: No. I have no idea.

HENN: It goes directly into the Elk Grove Police department.

UNIDENTIFIED MAN #3: That is kind of scary in a sense, just knowing that people are watching no matter what.

HENN: That man didn't want to give his name and that was true of many of folks in Elk Grove who told me they are apprehensive about these cameras. But people like Chelsea Yokkum, who were comfortable giving their names, were also OK with the cameras.

YOKKUM: I like the idea of it personally because I have a son of my own, you know? Do you want to reach that one?

UNIDENTIFIED BOY #1: No, no, no. No, reach that one. Reach that one.

YOKKUM: OK.

HENN: This community has invested hundreds of thousands on surveillance and plans to spend even more. After all, another playground a few blocks from here - one without a camera - was burned to the ground this spring, a suspected arson. Let's head across town to meet the man building this network.

CHRIS HILL: My name is Chris Hill. I am the IT manager here at the Elk Grove Police Department.

HENN: We are walking into the server room that runs the system. Wow, it's loud in here.

HILL: You can get camera feeds, you can make up any screens you want, you can search any video.

HENN: More than 100 feeds are viewable and searchable from Chris Hill's desk.

HILL: This other one here is actually in a parking lot. This was a known spot in the city of Elk Grove that had a high rate of car burglaries.

HENN: So we are watching a woman now open up her mini-van door.

HILL: Mm-hmm. And as soon as she drives off we can follow her out of the parking lot and down the street as well.

HENN: Wow. So you can read plates?

HILL: Absolutely. So this is probably 100 yards away and you can very easily read that license plate even as that car is moving.

HENN: All these cameras together record more than four days of video each hour, and Hill would like even more.

HILL: So we actually have a pilot project coming up - hopefully shortly - with a local retailer that will be giving us access to their parking lot cameras.

HENN: But Hill doesn't want his officers spending time watching parking lots, writing down plate numbers. The software can do that for them. And to see how, I traveled to San Francisco and the offices of 3VR.

AL SHIPP: Most people don't understand that putting more cameras doesn't necessarily yield more information.

HENN: Al Shipp is the CEO. His company makes the software Elk Grove uses to sift through its recordings. They offer facial recognition, license plate readers and object based searches.

SHIPP: Instead of watching hours and maybe days of video, you can ask questions like: show me all red cars that went east. Those are search arguments that you can do with our technology and literally sort through weeks of video in a few seconds.

HENN: The software can alert the police when someone enters a park after dark. Or can search for a face.

DIEGO SIMKIN: Yeah. So this person was captured at 2:18.

HENN: Diego Simkin is a technician at 3VR.

SIMKIN: So what I would do is I'd right click here, search for this person. I have the ability to not only search for this specific camera but I can search against multiple cameras on that system or multiple systems.

HENN: And that kind of ability to expand a video search is a major draw for police in Elk Grove and departments across the country. This industry is growing by 30 percent a year and the software alone is poised to become a billion dollar business. In the nation's capital some are watching with concern.

LAURA DONOHUE: The idea that all this information will be fed into one place I think is a game changer in terms of how we look at our world.

HENN: Laura Donohue is a Law professor at Georgetown. She says while it is reasonable to expect that someone one will see you lying in a public park...

DONOHUE: You do have a reasonable expectation that nobody is going to be following you around 24 hours a day, seven days a week everywhere you go.

HENN: And Donohue worries that's were these systems, like the one in Elk Grove, seem to be headed.

MINA FARDAN: That's a camera?

HENN: That's a camera. Yeah.

FARDAN: Cool. Oh, surprising. They should let people know.

HENN: Even, Mina Fardan says, if those people are just picnicking in Miwok Park and have nothing to hide.

UNIDENTIFIED BOY #2: I'm hiding something.

HENN: Not from the camera. The camera is right behind you.

(LAUGHTER)

HENN: I'm Steve Henn for the NPR Cities Project.

(SOUNDBITE OF MUSIC)

INSKEEP: This is NPR News.

And you can go online and find other stories about smart cities. And if you don't look for them, don't worry, they'll find you. They're at npr.org/nprcities.